perlPackages: remove search.cpan.org; add metacpan.org default homepage

https://www.perl.com/article/saying-goodbye-to-search-cpan-org/

maybe one operation less

..with unifying recursiveUpdate and first //

although not tested

fix whitespace

pkgs/development/perl-modules/generic/default.nix

@@ -3,6 +3,8 @@ perl:
 { nativeBuildInputs ? [], name, ... } @ attrs:
 
 perl.stdenv.mkDerivation (
+  (
+  perl.stdenv.lib.recursiveUpdate
   {
     outputs = [ "out" "devdoc" ];
 
@@ -20,9 +22,11 @@ perl.stdenv.mkDerivation (
     # authors to skip certain tests (or include certain tests) when
     # the results are not being monitored by a human being."
     AUTOMATED_TESTING = true;
+
+    meta.homepage = "https://metacpan.org/release/${(builtins.parseDrvName name).name}";
   }
-  //
   attrs
+  )
   //
   {
     name = "perl-" + name;